Abstracts

Rationale: Medically intractable epilepsy affects ~23% of all a patients with epilepsy, with the highest prevalence occurring in children less than 5 years of age. The Vagal Nerve Stimulator (VNS) is an approved adjunctive therapy for non-surgical epilepsy in adolescents and adults; however, its efficacy in children with medically intractable epilepsy is poorly understood. We sought to determine the efficacy of VNS therapy as an adjunctive treatment in this pediatric patient population. Methods: Methods: We retrospectively identified patients with a diagnosis of medically intractable epilepsy who were less than 3 years of age when they underwent VNS placement at Children's Hospital of Pittsburgh between July 2004 and August 2011. Only children with longer than 1 year follow up information were included in this study. Primary outcome variable was change in seizure frequency pre/post VNS at 1 year follow-up. Epilepsy syndrome at the time of surgery was classified by the investigators. Digital EEG was re-reviewed when necessary. Detailed information about VNS setting was included to analyze the relation to the primary outcome. Results: Seventeen patients underwent VNS placement during the study period. Two patients were excluded due to lack of follow-up. Final analysis included 15 patients (male 59%). Thirteen patients (87% of our cohort) had a symptomatic etiology. Median age of epilepsy onset was 3.25 months (range 1m-15m). Median age of surgery was 25 months (range 12m-35m). The most common epilepsy syndromes were Dravet Syndrome (n=3) and West syndrome (n=3). Average of five antiepileptic medications were tried prior to VNS placement. Five patients (33%) showed a 50% reduction in seizure activity at 1-year follow-up. Among epilepsy syndromes all Dravet Syndrome patients (n=3) displayed seizure reduction (p = 0.05), while no patients with West Syndrome/Lenox-Gastaut Syndrome showed reduction (p = 0.07). VNS rapid cycle settings was used 4 patient at one year follow-up with no difference in seizure reduction in comparison to regular VNS settings (p = 0.3). No complications from VNS placement were reported. Conclusions: VNS placement was well tolerated in children less than 3 years of age in our institution. The rate of seizure reduction was modest in our patient population at one year follow up, which could be secondary to large proportion of our cohort with epilepsies of symptomatic etiology.. Patients with Dravet Syndrome appeared to benefit the most and could represent a suitable adjunctive therapy for this patient population. Futher studies, including longer follow up evaluations, are warranted.